Mix and match of vaccines not country policy

Some Kenyans fancy getting the AstraZeneca jab then Pfizer “to boost immunity” but mixing and matching of vaccine doses is discouraged by both the Ministry of Health and the World Health Organisation (WHO).

So far Kenya has received four vaccines; AstraZeneca, Moderna, Johnson & Johnson and Pfizer. Sinopharm from China is also expected, and with these options, Kenyans are still wondering why they cannot mix them. 

The chairperson of the Covid-19 Vaccine Taskforce Willis Akhwale says it has emerged that some Kenyans who went for the first dose of AstraZeneca are waiting for another dose, say, Johnson & Johnson, for their second dose. But mixing and matching, warns Dr Akhwale, is not a policy in Kenya. “Right now we have enough doses of Astra Zeneca, so let them come and receive their doses,” he says.

So far there are more than 100,000 people in Kenya who went for their first jab but have defaulted on their second, yet the WHO has emphasized that mixing vaccines is dangerous on the face of scanty data on their impact on health.

Prof Julius Oyugi, a virologist at the University of Nairobi, says lack of data is reason enough to discourage full vaccination using mix and match methods, as their levels of efficacy are not yet known. This, Prof Oyugi adds, is despite studies that revealed that having AstraZeneca as first dose and Pfizer as second saw people develop good immunity.

Pfizer was initially an emergency vaccine, but has since received full approval by the United States Food and Drug Administration (FDA) and can be used for those aged 16 and above. Moderna has also sought FDA approval, but AstraZeneca and Johnson & Johnson are still under emergency use authorisation.

Oyugi said the difference between authorisation and full approval purely lay with the duration the vaccine had taken to undergo vigorous training in humans, which is at least one year for data to be collected on safety and effectiveness among tens of thousands of people.

“But in pandemics, if we can weigh the use of the vaccine or the risks of using outweighs the effects of the pandemic then we give emergency authorization as data continues to be collected,” he said adding that with or without full approval, even vaccines under emergency use perform similar functions of preventing one from severe illness.

According to WHO, the best vaccine is the one you can get today and people should get vaccinated with whatever Covid-19 vaccine is available.